Mitigation of arsenic stress in Brassica juncea L. using zinc oxide- nanoparticles produced by novel hydrothermal synthesis

In the current study, we successfully synthesized the zinc oxide nanoparticles (ZnO-NPs) via an efficient, fac-ile, and cost-effective method of the modified hydrothermal synthesis approach, and examined their effec-tiveness in alleviating arsenic (As) stress in Brassica juncea. The synthesized ZnO-NPs were analyzed using a variety of experimental techniques viz. XRDs, SEM micrographs, EDAX/Mapping pattern, Raman Spectros-copy Pattern, and X-ray photoemission spectroscopy analysis. All of these analyses revealed that ZnO-NPs were highly pure with no internal defects and could potentially be used in plant applications. Hence, we fur-ther determined the effect of these nanoparticles in modulation of As tolerance in B. juncea plants by examin-ing the various growth attributes, photosynthesis parameters, antioxidant activities, and enzyme activities. Our results demonstrated that As-stress inhibited growth, photosynthesis-related parameters, reduced pro-tein content, as well as carbonic anhydrase, nitrate reductase, and RuBisCO; however, these attributes were substantially up-regulated by the supply of ZnO-NPs to the leaves. Furthermore, As stress-induced increases in malondialdehyde and H2O2 levels are partially reversed by ZnO-NP in the As-stressed plants. Overall, sup-plementation positively regulated As tolerance in B. juncea by altering the key enzymes involved in ROS detoxification, which in turn prevented As-induced oxidative damage to the plant tissues. Hence, our study clarified the potential involvement of the newly synthesized ZnO-NPs in alleviating As stress in plants. Fur-thermore, this is the first report to elucidate the effect of the ZnO-NPs synthesized by the hydrothermal reac-tion route on As-stress modulation in B. juncea. (c) 2023 SAAB. Published by Elsevier B.V. All rights reserved.